It always cracks me up when a seller says their mileage is "all highway miles". How is that even possible?

Sorry, I should have said mostly highway miles. I can tell you that that my job requires me to do a lot of travelling. I spend 80% of my driving on the interstate. Is it 100%? No, but do you really think I meant 100%

If I were to sell my car, I would tell the potential buyer that the miles are all, oh excuse me mostly, highway miles.